Field of the Invention
The present invention is a method for detecting. More specifically, the present invention is a method for detecting a disease by analysis of retinal vasculature such as Alzheimer's disease.
Description of the Related Art
The hallmark sign of Alzheimer's disease or AD may be a build-up of amyloid beta plaque in a person's retina. While amyloid may be detected in the brain with amyloid positron emission tomography or PET imaging, the resolution may be relatively low and there must be a meaningful accumulation in order to achieve a positive scan.
In evaluating postmortem retinas, there may be accumulation of amyloid beta plaques in the interior walls of blood vessels resulting in a thinning of the lumen or interior of the blood vessels. From various measurement techniques, it was observed that patients with thinning vessel lumen may be more likely to be at risk for Alzheimer's disease, mild cognitive impairment or MCI or actually have AD. These techniques hold promise as a means of detecting AD prior to symptoms and at relatively early stages as amyloid may build-up to approximately twenty years ahead of the onset of cognitive decline. This may be a basis of a method for determining a level of disease or a risk of obtaining a disease by monitoring changes over a predetermined period of time.
While the method for detecting a disease such as Alzheimer's disease by analysis of retinal vasculature may be performed with traditional fundus cameras, scanning laser ophthalmoscopes with small confocal apertures produce relatively superior results. The utilization of infrared or IR imaging from a scanning laser ophthalmoscope or SLO is relatively more comfortable and advantageous in elderly patients with lens opacities, since light is scattered relatively much less in the presence of media opacities. IR-mode imaging in a confocal scanning laser ophthalmoscope may be utilized to image the retina with an infrared laser. The proposed imaging methods may employ a small confocal aperture to reject light from areas other than the intended focal plane. Vessels may be imaged with the technique and result in sharper edges and reduce scatter.
While the method may be helpful in detection of vessel walls and lumen, the combination of the method with super-resolution and other image processing and analysis techniques may yield a method that may detect changes in a wide variety of vessels, at relatively early stages of disease and also track the changes over a predetermined period of time.
Amyloid beta plaque may be identified in a human brain however identification of the deposits at the relatively earliest stages of disease and of a relatively small size may be impossible with existing retinal imaging technology. This problem may be solved through a combination of IR mode illumination techniques utilizing a confocal laser scanning ophthalmoscope in combination with super-resolution image processing techniques that afford for the imaging of vessel walls and vessel interior lumen that previously were of inadequate quality for measurement with other imaging modalities. Multi-image super-resolution techniques allow recording a series of images and then combining their data set to produce images of relatively extraordinary resolution and image quality thereby resolving the fine details of vessel edges and lumen at relatively early stages of disease. Furthermore, tracking changes in vessel walls and lumen thickness or thinning, size, area, density, reflectivity over time may be likely an indicator of advancing disease and rate of advancing disease. These aspects have never been studied.